431 research outputs found
Electroweak and QCD aspects in V+jets in CMS
No full textThe study of the associated production of vector bosons and jets constitutes an excellent testbench to check numerous QCD predictions. Total and differential cross sections of vector bosons produced in association with jets have been studied in pp collisions at 7, 8 and 13 TeV center-of-mass energies. Differential distributions as function of a broad range of kinematical observables are measured and compared with theoretical predictions. Final states with a vector boson and jets can be also used to study electroweak initiated processes, such as the vector boson fusion production of a Z or W boson that are accompanied by a pair of energetic jets with large invariant mass.The study of the associated production of vector bosons and jets constitutes an excellent testbench to check numerous QCD predictions. The most recent measurements of total and differential cross sections of vector bosons produced in association with jets are presented. Differential distributions as function of a broad range of kinematical observables are measured and compared with theoretical predictions. Final states with a vector boson and jets can be also used to study electroweak-initiated processes, such as the vector boson fusion production of a Z or W boson accompanied by a pair of energetic jets with large invariant mass. The study of these processes enables quantitative assessment of the reliability of the generator predictions for vector boson fusion topologies as well as stringent constraints on anomalous triple gauge coupling effective field theory parameters
Search for a Standard Model Higgs boson produced in association with a W or Z boson decaying to bottom quarks
No full textA search for a Standard Model Higgs boson decaying to b produced in association with a W or Z boson is reported for the following channels W(e)H, W()H, W()H, Z(H, Z(ee)H, and Z()H. The search is performed on data samples corresponding to integrated luminosities of 5.1 at TeV and 18.9 at TeV, collected by the CMS experiement at the LHC. An excess of events is observed above the expected background with a local significance of 2.1 standard deviations for a Higgs boson with mass 125 GeV consistent with Standard Model expectations. The signal strength corresponding to this excess, relative to that of the Standard Model Higgs boson, was 0.89 0.43
Observation of Higgs boson decay to bottom quarks
No full textThe observation of the Standard Model Higgs boson decay to a bottom quark-antiquark pair is presented. The primary contribution to this result is from processes in which the Higgs boson is produced in association with a W or Z boson. The latest measurement of these processes is described, using 41.3/fb of proton-proton collision data at center-of-mass energy √s = 13 TeV, collected by the CMS experiment in 2017. The significance of the observed excess in data over Standard Model backgrounds is 3.3 standard deviations. The result is combined with similar measurements performed by CMS on previous datasets, resulting in an observed significance of 5.6 standard deviations. The measured signal is well consistent with the Standard Model expectation for a Higgs boson with mass 125 GeV decaying to bottom quarks, with a precision of 20%
Observation of Higgs boson decay to bottom quarks
No full textThe observation of the Standard Model Higgs boson decay to a bottom quark-antiquark pair is presented. The primary contribution to this result is from processes in which the Higgs boson is produced in association with a W or Z boson. The latest measurement of these processes is described, using 41.3/fb of proton-proton collision data at center-of-mass energy √s = 13 TeV, collected by the CMS experiment in 2017. The significance of the observed excess in data over Standard Model backgrounds is 3.3 standard deviations. The result is combined with similar measurements performed by CMS on previous datasets, resulting in an observed significance of 5.6 standard deviations. The measured signal is well consistent with the Standard Model expectation for a Higgs boson with mass 125 GeV decaying to bottom quarks, with a precision of 20%
Higgs Couplings in CMS in Run2
No full textThe latest results on Higgs boson couplings using Run-2 data collected by the CMS experiment are presented. These recent developments include the confirmation of what had been the two remaining third generation Yukawa couplings yet to be observed, the top quark and bottom quark couplings. Next, the latest search for the rare Higgs boson decay to a muon-antimuon pair is presented, which should soon give access to the first measurement of a second generation Yukawa coupling. The most stringent limit to date is then shown for the branching fraction of the Higgs boson to undetectable invisible signatures. Finally, the first search for the extremely rare decay of the Higgs boson to quarkonia is shown
Observation of Higgs boson decay to bottom quarks
No full textThe observation of the Standard Model Higgs boson decay to a bottom quark-antiquark pair is presented. The primary contribution to this result is from processes in which the Higgs boson is produced in association with a W or Z boson. The latest measurement of these processes is described, using 41.3 fb of proton-proton collision data at center-of-mass energy = 13 TeV, collected by the CMS experiment in 2017. The significance of the observed excess in data over Standard Model backgrounds is 3.3 standard deviations. The result is combined with similar measurements performed by CMS on previous datasets, resulting in an observed significance of 5.6 standard deviations. The measured signal is well consistent with the Standard Model expectation for a Higgs boson with m = 125 GeV decaying to bottom quarks, with a precision of 20%
BSM H searches and rare H decay searches at CMS and ATLAS
No full textSearches for rare Higgs boson decays and extensions of the Higgs sector beyond the standard model are key to probing the dynamics of electroweak symmetry breaking. With the large LHC Run-2 dataset, considerable progress has been made in probing the largely unexplored Higgs boson interactions with the lighter fermions, as well as in searching for signs of new physics in the Higgs sector with mass scales ranging from 100 MeV to several TeV. The results presented here are either brand new for this conference, or were released in the weeks just before
Can Nuclear Power Be Part of the Solution?
No full textThe author discusses the importance of incorporating the full costs of operating a nuclear power plant in the U.S., such as climate impact, risk of accidents, and safe disposal of radioactive waste. He argues on the need for changes in the country\u27s evaluation of nuclear power which include the elimination of subsidies, and the requirement to buy full-coverage insurance for accidents. The author further highlights the cost of greenhouse gas emissions from nuclear power plants
On the Use of a Cash Flow Time-Series to Measure Property Performance
No full textModern portfolio theory is increasingly being used to guide real estate portfolio decisions. However, to obtain meaningful results from complex mathematical techniques, the input data must meet at least two conditions: property values must be measured accurately, and the process by which property valuations change over time must be known. Neither of these conditions are satisfied by data currently available. This paper closely examines how value is measured and reported for commercial property. Commonly used time-series from NREI, NCREIF and ACLI are found wanting. An index of value using the popular "repeat sales" method is derived using data from Freddie Mac's multifamily portfolio. The focus of this paper is on developing an alternative measure of property performance based on property net operating income. Two cash flow indices are constructed from publicly available data and evaluated. It is recommended that the methodology developed here be used to create cash flow indices that can supplement or replace existing value indices in property analysis. The cash flow indices have much to offer researchers applying option-based models to real estate.
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